Punch interposer arrangement and associated selection means



Nov. 26, 1968 E. E. MASTERSON ET AL PUNCH INTERPOSER ARRANGEMENT ANDASSOCIATED SELECTION MEANS 5 Sheets-Sheet 1 Filed July 14, 1966INVENTORS DAV/D w. BERNARD EARL E. MASTERSON v CHE/VG-HUA WANG 8)MICHAEL s. smsamvow WRTQZZZ NOV. 26, 1968 E, E, MASTERSQN ET AL3,412,932

PUNCH INTERPOSER ARRANGEMENT AND ASSOCIATED SELECTION MEANS Filed July14, 1966 5 Sheets-Sheet 5 INVENTORS DAV/D W. BERNARD EARL E. MASTERSO/VCHE/VG-HUA WANG MICHAEL S. SHEBANOW Nov. 26, 1968 E. E. MASTERSON ET AL3,412,932

PUNCH INTERPOSER ARRANGEMENT AND ASSOCIATED SELECTION MEANS 5Sheets-Sheet 4 Filed July 14, 1966 Fig. 7

Nov. 26, 1968 E. E. MASTERSON ET AL 3,412,932

PUNCH INTERPOSER ARRANGEMENT AND ASSOCIATED SELECTION MEANS 5Sheets-Sheet 5 Filed July 14, 1966 lNVE/VTORS DAVID W. BERNARD EARL E.MASTERSO/V CHENG-HUA WANG MICHAEL S. SHEBAIVOW United States PatentPUNCH INTERPOSER ARRANGEMENT AND ASSOCIATED SELECTIGN MEANS Earl E.Masterson, Newtonville, David W. Bernard, Sherhorn, Cheng-hua Wang,Newton (Ienter, and Michael S. Shebanow, Medfield, Mass., assignors toHoneywell Inc-, Minneapolis, Minn., a corporation of Delaware Filed July14, 1966, Ser. No. 565,251

18 Claims. (Cl. 234-115) ABSTRACT OF THE DISCLOSURE For an actuatorarrangement including a flexible-strip interposer, improved magneticfeatures for thrusting the interposer into, and out of, actuatingcondition magnetically, including such features as: opposed fiuxgenerating means (permanent versus solenoidal, in certain cases) with aferromagnetic interposer flexure; a nonmagnetic guide sheet interceptingthe working gap; individual pole pieces for each flexure; a commonpermanent magnet for each aligned set of such pole pieces; and anadjustable flux-shunt between the common magnet and the pole pieces.

This invention relates to mechanisms for perforating computer recordmedia selectively; more particularly it relates to a high-speed computerpunch arrangement including an improved flexure interposer arrangementand an improved simplified magnetic selection arrangement associatedtherewith for providing faster, more reliable, punching operation, aswell as simplified construction and maintenance characteristics.

Electronic data processing apparatus has placed a great emphasis uponoperating associated terminal (input/output) mechanisms, such as ahigh-speed punch, with everincreasing speeds, yet with no sacrifice inreliability. The commercial environment of data processing mechanismshas further complicated the design constraints of such terminalequipment by requiring that it be relatively simple and inexpensive toproduce, and especially that it be relatively maintenance-free. This isparticularly true in view of the very expensive down time costs thatresult when any mechanical component fails so as to interrupt theoperation of the high-speed electronic data processing system, whosehourly operating costs are extremely expensive. Therefore, a primaryobject of the invention is to provide a high-speed computer punchmechanism capable of operating at very high speeds, yet with reliabilityover a reasonably long life. A related object is to provide such apunching mechanism employing deflected flexure strips, as interposermeans for selectively applying punching thrust to associated punches andto provide improved magnetic means therefor. A further related object isto provide improved magnetic selection means and associated magneticmeans to actuate such fiexure-interposers for control of selectivepunching thereby.

Another object is to provide, for such an array of interposers andassociated punches, a magnetic selection means comprising a pair of polepieces for directing permanent magnetic flux operatively through eachsuch interposer, in combination with a single common permanent magnettherefor. A related object is to provide adjustable magnetic shunt meansbetween such pole pieces and such a permanent magnet for adjusting thestrength of the field passing therebetween.

Still another object is to provide such an array of pole pieces andassociated interposers and to include compensating pole and relatedmeans to reduce magnetic edge effects, fringing fields and the like forthe outboard interposer arrangements. Another object is to provide withsuch an array, bidirectional interposer actuation means includingopposed retain/release means. Still another object is to provide such anarray of pole pieces in combination with bucking solenoid means adaptedto oppose such permanent magnetic flux. A further object is to providesuch solenoid means arranged to selectively activate interposers to anon position, otherwise permitting them to be held fail-safe by saidpermanent magnetic flux.

A still further object is to provide such an array of pole pieces andassociated flexure interposers with integral sheet guide means along alinear set thereof. Another object is to provide such an arrangementincluding nonmagnetic punch construction to prevent erroneous punchtranslation.

According to a preferred embodiment of the invention, a high-speedserial card punch mechanism is provided to include two rows of alignedpunches; a continually oscillating bail structure; two rows offlexure-interposer means mounted on the bail, each flexure arraycontrollably actuated into driving registry with respective ones of saidpunches by a linear array of magnetic selection elements, each elementactuating a respective flexure and comprising a pair of pole piecesoperatively confronting the flexureinterposer and adapted to continuallydirect permanent magnetic flux therethrough for maintaining the flexurebiased (deflected) to a normally off condition, being also provided withbucking solenoid means for selectively releasing the flexure into oncondition by opposing this flux. In addition, a permanent magnet isprovided to so energize such a set of pole pieces and magnetic shuntmeans is also provided therebetween to adjust the effective strength ofthe permanent magnet field at the flexures. Also a plurality of magneticfield directing and compensating means is provided adjacent theoperative magnetic select elements and interposer/punch elements.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of the preferred embodiment of the invention as illustratedin the accompanying drawings, wherein like reference numerals denotelike elements:

FIGURE 1 is an idealized perspective showing of high speed card punchembodiment of the present invention, some parts being omitted and somesimplified for clarity;

FIGURE 2 is an enlarged sectional view of the arrangement in FIGURE 1 inthe up, or nonpunching, phase;

FIGURE 3 is an isometric exploded view of one of the interposerassemblies of FIGURE 1 together with associated strippers, punches andmagnetic select means, the interposer guide means therein being slightlymodified;

FIGURE 4 is a front elevation of the magnetic shunt portion of one ofthe selection assemblies in FIGURE 1;

FIGURE 5 is a simplified sectional view of operating punch andinterposer elements as in FIGURE 2, however, indicating the Down, orpunching, phase;

FIGURE 6 is a fragmentary sectional view, much enlarged, of one of thepreforms in FIGURE 3; and

FIGURE 7 is a very schematic idealized sectional front view of the polepieces in one of the selection assemblies in FIGURE 1.

In general With reference now to the drawings, the invention Will beexplained by way of an embodiment which implements an interposerarrangement for a two column (12 punches per column) high speed serialpunch apparatus. This arrangement, as best seen in FIGURE 1, is acombined interposer-actuator unit A, shown in operative relation with apair of associated multipunch magnetic selection arrays ML, MR. Unit Aincludes a pair of like multipunch interposer assemblies IL, IR, eachbeing arranged to drivingly connect a driving means, in the form of apunch bail (bail frame H being shown) with selected punches in anassociated aligned set of punches P, P (FIGURE 3). These elements,generally, implement the high speed serial punch, the functions of whichare known and more particularly described in copending application Ser.No. 402,412 (now issued as U.S. Patent No. 3,279,- 690), commonlyassigned. In essence, an eccentric drive shaft (not shown here) isarranged to rotate at high speeds (for instance, about 5,000 rpm.) so asto constantly reciprocate the bail (frame H) in a nearly-linear punchingmotion, as understood in the art. This bail is preferablyflexure-coupled to the drive shaft and also is preferablyflexure-suspended from a mounting support, as indicated in theaforementioned application. Bail frame H includes a shaft-couplingheader portion HF. According to a feature of the invention, frame H isarranged to be integral with a set of projecting, subtendedmultipunchpair stripper means comprising stripper array ST (FIG- URES 1,3).

Paired interposer assemblies IR, IL are mounted on bail H to berelatively symmetrical about stripper array ST. Assemblies IR, IL areidentical, each including a multifingered interposer fiexure sheet 30,30 respectively (only 30 is shown in FIGURES 1, 3), each finger 3, 3'thereof being arranged to be selectively positioned to drive anassociated one of punches P, P respectively when the latter is selected.In the illustrated punch unit, two columns or sets P, P of 12 puncheseach, are shown, being understood as act-uable for selectively punchingassociated rows and columns in a passing computer record such as.

a punched card. It will be understood that the record medium is to bemoved in a conventional manner below the lower punch ends, as is wellunderstood in the art.

Thus, actuator unit A, being operatively arranged between left and rightmagnetic assemblies ML, MR, respectively, comprises a bail frame H, astripper assembly ST projecting integral therebelow and a pair of leftand right interposer assemblies IL, IR, respectively, the latter beingattached to H to be symmetrical about stripper assembly ST. Assembly MLis shown exploded laterally away from unit A only for illustrationpurposes. Thus, the left columnar row (set) of punches P1 through P12 isdisposed so that each punch may be selectively engaged for punchingactuation by an associated one of interposer flexure fingers 31 through312 respectively (only a portion being shown in FIGURE 3) of associatedinterposer flexure sheet 30 in left interposer assembly IL. Similarly,for companion set of punches P1 through P'12, which are disposed inoperative relation with respective fingers 3-1 through 3-12 (not shown)of interposer flexure sheet 30 in right interposer assembly IR.

As seen in FIGURES 1 through 3, the stripper array ST projectsintegrally from frame H to comprise a central body portion of actuatorunit A and includes a plurality of stripper extensions ST1 through ST13,each terminating in an enlarged head portion sh. Adjacent pairs of headssh are adapted to engage opposite sides of respective paired punches, asseen hereinbelow. Stripper extensions ST1 through ST13 are separated byprescribed cutout slots SC-l through SC-12, fashioned to be just aboutwide enough to admit an associated pair of punches therealong, such aspaired punches P1, P1 in slot SC-l. Stripper heads sh are engaged alongassociated slots pg formed along opposite sides of each punch. Slots pgare arranged so that heads sh may travel therealong and may engage theupper limit thereof just after punching is completed, i.e. when bail Hhas bottomed in its downward thrust, the unselected punches being heldup (by retainer meanssee below) while heads sh begin to return theselected punches as bail H returns upwardly. Thus, a surrounding pair ofconfronting heads sh will engage a punch after it has bottomed toretract it (strip it) and return to to the unactuated (or UP positionshown in FIGURE 2), being thus automatically returned upward with bailH.

Punches As is somewhat conventional in the art, punches P are aligned inprescribed lateral positions by guiding bores in a die means D, so as tobe drivenly engaged by respective ones of flexure fingers 31 etc.Punches P are also arranged to be maintained in the aforementioned UP,or rest, position when not selected, being so maintained by retainermeans (SP, FIGURE 2) engaged therewith. More particularly, as FIGURE 2shows, a retainer flexure spring SP is provided in a slot ps in eachpunch P, for instance, spring SP-l being provided for punch P-l, springSP1 for companion punch P1, etc. Slots ps have their upper limits offsetbetween paired punches (those in punches P offset from those in punchesP) to allow associated retainer springs SP, SP to be similarly offset,and non-interfering, while projecting from a common base. The upwardthrust of these retainer springs may be stoplimited to establish aprescribed up-plane RR (FIG- URES 2, 5) for the tops thereof, just belowthe driving interposer flexures 3, and out of engagement therewith. Asimple stop means as indicated at stop bar SX (FIG- URE 2) projects fromthe rigid frame to effect this, being stoppingly engaged by the lowerend of stop grooves ps of paired punches along a common plane. Thus,slots ps will be of difierent lengths to accommodate the differentengaging position for retainer springs SP, SP, yet terminated along acommon plane by stop SX. As those skilled in the art will appreciate,other equivalent retainer and stop means may be provided.

Each punch is also provided with a magnet MG for punch verificationpurposes. Magnets MG comprise permanently magnetized material carried bythe punches and adapted to be brought operatively adjacent an associatedverification detector PCM when the punch is properly driven to itsmaximum bottoming excursion (down position). Thus, by sensing thepresence of the magnets, each detector PCM provides a verifyingindication that its associated punch has perforated the record.

Punches P are comprised of tool steel or other tough metal. Preferably,the top portions PT of punches P are separately fabricated to comprise ahigh durability, wearresistant, non-magnetic material, such as Stellite(trade name), and are atfixed, such as by welding or the like, to themain shank portion of the punch. This provides a durable,impact-resistant tip for driven engagement with the associated fiexureinterposer finger. This tip material is also specified as non-magneticto prevent false punch-translations (explained below), i.e. not to becarried downward to activate detector PCM when bail H descends if thepunch is not selected. Such may occur if a punch becomes magnetized andis magnetically attracted to follow a moving magnetized part. Forinstance, stripper heads sh may become magnetized by the adjacent fieldsfrom the magnetic assemblies MR, ML, etc., and, in turn, might attractan adjacent punch tip to follow them toward the down position. It willbe appreciated by those skilled in the art that such false translationsof a nonselected punch P are intolerable; for instance, they interferewith the transport of a passing record and also can induce a false punchecho (punch verification signal) from detector PCM. In this connection,it will also be appreciated that stripper projection ST, includingstripper arms ST-l through ST-13 and associated heads sh, is preferablycomprised of a nonmagnetic, preferably demagnetized, tool steel or thelike so as to be tough and strong, and yet retain no magnetization suchas might falsely translate one of the punches, as aforesaid.

Magnetic selection FIGURES 1 and 3 show the environment in whichinterposer assemblies IL, IR are arranged, being clamped on bail H to besymmetrical about stripper assembly ST, and also to be symmetricallysurrounded by the left and right magnetic assemblies (ML, MR,respectively). Leftward magnetic assembly ML includes an elongate,strongly magnetized, permanent bar magnet 23 enclosed in a nonmagnetic(preferably aluminum) casing 21 to which upper and lower sets of polepieces, 27, 29 respectively, are attached. Magnet 23 comprises astrongly ferromagnetic material and includes a pair of oppositepolarity, upper and lower projecting poles 23-P, 23-PP, respectively.Upper and lower sets of pole pieces 27, 29, respectively, comprise anumber of vertically paired, lowreluctance, flux-conducting membersmounted on casing 21 so as to be in operative flux-conducting relationwith upper and lower magnet poles 23-P, 23-PP, respectively. Lower polepieces 29 comprise fourteen spaced, relatively identical, projections29-0through 29-13 (a portion being shown in FIGURE 3 as well), allcantilevered out relatively orthogonal from lower magnet pole 23-PP tobe relatively orthogonal to the vertical bail (driving) axis V.Similarly, upper pole pieces 27 comprise a set of fourteen projections27-0 through 27-13, all cantilevered out from upper magnet pole 23-P atthe same oblique angle, being also oblique to axis V. Casing 21,preferably aluminum, is adapted to direct the flux from magnet 23 topole pieces 27, 29f

Upper pole pieces 27 thus extend downwardly toward a corresponding oneof the lower pole pieces 29 to be vertically registered therewith, thusforming fourteen identical pole pairs. Each of the twelve inboard polepairs 27-1/ 29-1 through 27-12/ 29-12 are thus disposed so that eachpair may project a permanent magnet flux somewhat normally toward therespective one of the twelve magnetic interposer flexure fingers 3-1through 3-12 with which it is operatively associated, being spacedtherefrom in opposing flux-coupled relation. Thus, each such pole paircan attract (and repel) a corresponding flexure toward (and away from)themselves, out of (and into) the thrust-transmitting, ON position (andthe OFF, or no-punch, position). These ON/OFF positions are indicatedfor flexures 3-2/3'-3, respectively, in FIGURE 4 and 3-1/3-1 in FIGURE5. The two outboard pole pairs in assembly ML, namely pole pairs27-0/29-0 and 27-13/29-13 (FIGURE 3) are not operatively associated withany interposer flexure, but are provided (as detailed below) to helpbalance the magnetic field for the outboard fiexures, 3-1, 3-12,respectively, in cooperation with the outboard strippers ST-l, ST-13. Asshown, all the pole pairs (27-0/2 9-0 through 27-13/29-13) are normallyset to apply flux from permanent magnet 23 to pull flexure fingers 3-1through 3-12 toward themselves, i.e., to be set normally OFF.

The twelve inboard, interposer-actuating, pole pairs are also eachprovided with a bucking solenoid winding about each (upper and lower)pole piece. These winding pairs, when current-pulsed, are each adapted,as seen below, to substantially cancel out the aforementionedflexure-attracting permanent magnet flux from their re spective pair ofpoles to selectively translate the associated flexure finger to ON(punching) position. Thus, a bucking solenoid winding is provided oneach of upper pole pieces 27-1 through 27-12, namely windings 27-31through 27-312, respectively; while, similarly, on lower pole pieces29-1 through 29-12, windings 29-31 through 29-312, respectively, areprovided, as is best seen in FIG- URE 3. Select means (not shown) willbe understood as provided to apply sufiicient select current to eachsuch pair of pole windings at times when the associated flexureinterposers are selected, i.e., to be released to ON for punching aselected associated punch. The field generated by this current thusbucks, and cancels out, the corresponding permanent magnetic flux,releasing the preflexed, pre biased flexure finger to be returned by itsnatural internal resilience to the ON or punch position. Punch positionis where the flexure engages the associated inner (punching) preform 5so as to be stiffened thereby while thrusting the associated punchthrough the record when carried down by bail H.

Thus, for example, when bail H is in UP (START) position of the punchingcycle thereof (i.e., at its upward extreme and ready to start downwardin a new punching cycle), if the record were to be punched at theposition thereon under punch P'-2, a punch-current (Select) signal wouldthen be applied through associated bucking coils 29-32/27-32 to opposethe permanent magnetic flux emanating from associated pole pieces29'-2/27-2 and holding associated interposer finger 3'-2 in OFFposition, i.e. engaged against outer preform 1. In this OFF position,interposer 32 is flexed a maximum and is biased to snap back againstinner preform 5' when released, thus bridging slot C-2 therein.Application of the aforesaid select-current signal so releasesinterposer 3'-2 to assume this ON position so that when bail H nextdescends the free tip 1T of the interposer, as stiffened by preform 5,will engage the head PP'-2 of punch P-2 to drive it down for punchingthat (selected) position in the record. When bail H, thereafter, ascendsto complete this punching cycle, the associated pair of stripper headssir-2, sir-3, engaged about head PP-2 (in slots pg therein) will, ofcourse, return P'-2 toward UP position for beginning the next punchcycle. Punch P'-2 may be similarly selected in the next cycle; or it maybe not selected, in which latter case the permanent magnet field frompoles 292/27-2 will be allowed to retain flexure interposer 3'-2 back inOFF position as indicated for interposer 3-1 in FIGURE 5.

Magnet 23 is comprised of a high retentivity, permanently magnetizedferromagnetic (high mu) material, while projecting pole pieces 27, 29are comprised of a low retentivity easily magnetizable material.According to a feature of the invention, magnetic assembly ML is alsoprovided with a flux-shunt 25, (FIGURE 4) movably clamped between upperpole piece set 27 and upper magnet pole 23-P to be adjustablypositionable between poles 23-P, 23-PP to assume various flux-shuntingpositions therebetween and establish a variable shunt-gay dy (shownfull-open in FIGURE 1 and partly closed in FIGURE 2). Thus, shunt 25 isa high permeability, lowreluctance material mounted fiux-couplinglybetween pole 23-P and pole piece set 27 while being set to return avariable portion of the magnetic flux from pole 23-P to magnet 23, thisportion varying inversely with the length of gap dy. Such shunted fluxis prevented from passing through, and between, paired ones of polepieces 27, 29. Shunt 25 thus adjusts the permanent magnet strength ofthe field emanating from pole pieces 27, 29 and may control the forceexerted thereby to pull associated flexure fingers 3 into the OFF (nopunch) position. Slots 25-S are provided in shunt 25 to accommodateclamp means for allowing this variable shunt positioning. As recognizedby those skilled in the art, such an adjustable shunt is an extremelyconvenient means for adjusting the net magnetic force upon theinterposer fiexures and thus is convenient 'for standardizing the pullof the magnetic assemblies (MR, ML) either during fabrication or in thefield. This makes the manufacturing tolerances and positioningtolerances less critical, both for assemblies ML, MR and for the overallactuator unit A.

It will be appreciated that magnetic shunt 25 (25' similar) may comprisea magnetic flux conducting, low reluctance material being affixed tocasing 21 to be adjustably positionable, i.e., to be moved up and downto create a variable shunting gap dy between the poles 23-P and 23-PP ofpermanent magnet 23. Shunt 25 is shown in FIGURE 1 as fully-open, thusrecirculating or returning a minimum amount of (substantially no)magnetic flux to permanent magnet 23; while being shown in FIGURE 2 ashaving reduced gap dy so as to return a greater portion of the magneticflux, thus preventing it from circulating through pole pieces 27, 29. Itwill be appreciated by those skilled in the art that such an adjustableshunt has advantageous uses especially in association with aflexure-interposer actuator unit, such as assembly A, where simplicityand ease of fabrication and maintenance are salient features. Forinstance, here, the

spacing between flexures 3 and interposer poles 27, 29 somewhatcritically affects the resultant magnetic field applied thereto, and maybe shuntadjusted. That is, provision of shunt will allow adjustment,both at the factory and in the field, in the strength of the permanentmagnet field emanating from poles 27, 29 to thus compensate forvariations in the characteristics of affecting parts, from unit to unit.For instance, in the manufacture, the heat treating and the handling ofpermanent magnet 23, magnetic characteristics may be introduced thatvary from unit to unit. Similarly, if pole arrays 27, 29 aremanufactured by different people at different times, their dimensions,metallurgy, etc., may vary somewhat, as may their mounting positionrelative to fiexures 3. Such variances in manufacturing tolerances canbe compensated for by varying shunt position to normalize the emanentfield. For example, shunt gap dy may be set to a prescribed (e.g.,one-half) gap until final assembly when it may be adjusted up or down tonormalize the emanant field when the net effect of manufacturingvariations has made the field a little too strong or a little too weak,respectively. Similarly, linear variations in characteristics along oneset of pole pieces can also be compensated for by this shunt; forinstance, skewing it longitudinally so that gap dy is greater at one endof magnetic array ML than at the other. Alternatively, individual shuntsmay be provided for each set of pole pieces 27-1/29-1, etc.

It is quite apparent, of course, that such individual shunts act tocouple the permanent magnet and solenoid pole pieces in a characteristicmanner. Such a shunt, being freely adjustable, may be disposed to bridgeall, or a portion, of the interpole-piece gap (dy). For example, a shuntpiece 25 may be permanently fixed to bridge the entire base-gap betweenpole pieces 27-1, 291 and thus, inherently, form a flux-return path(since it will inherently provide a lower reluctance path than theoutside air). Thus, in certain cases the shunt 25 will comprise a sheetof metal bridging both the permanent magnet pole faces and the polepieces to provide a flux path for both entirely along its length (ratherthan being adjustable as illustrated). It should be realized that,besides shunting a portion of perman nt magnet flux as aforementioned,the additional shunt function of solenoid flux return is quiteadvantageous. For instance, it has been noticed that this greatlyalleviates the common problem of cross talk" (between adjacentmagnets-often a vexing problem, as workers in the art well know). Itwill, of course, be apparent that such cross talk leakage can act toundesirably couple adjacent magnets so that they affect, and degrade,one anothers operation. This is undesirable because it makes itimpossible to normalize the flux condition of a magnet assembly since,being influenced by its neighbor magnet, one cannot predict whether thatneighbor will be on or off (the inductive coupling between the two beingdifferent in either case) and hence cannot reference upon a singlenormal environment.

Of course, other magnetic means may be provided to perform theseinterposer-positioning functions of magnetic assembly ML. For instance,magnetic means might be mounted adjacent each fiexure 3, on the bail, totranslate it to OFF position selectively, in advantageous relation withthe light, self-restoring flexure. It will also be understood thatmagnetic assembly MR, arranged symmetrically on the opposite side ofactuator unit A and having similar parts (with same numerals, butprimed) is arranged identical to comparison assembly ML described above,MR being adapted to control the ON, OFF (punch, no-punch) positioning ofassociated interposer flexures 3' in the corresponding interposerassembly IR.

FIGURE 7 will summarize the features and operation of this magneticselection assembly, illustrating, in front elevation, the paired polepieces thereof in relation with one another and with associated fiexureinterposer means (in phantom). Here a set of fourteen pairs of polepieces comprising magnetic assembly ML (assembly MR is similar, ofcourse) appears, with associated magnetic shunt 25 being exploded awayfor clarity. FIGURE 7 thus shows frontally only the pole tips of thefourteen pairs of poles 2743/2941 through 2713/2913 of magneticselection assembly IL, indicated in FIGURES l and 3 especially. Theflexure strips 3 associated with the inboard pole pairs 27I/29-1 through2712/2912 are indicated fragmentarily and in phantom, as 31 through3-12, respectively. FIGURE 7, though not necessarily to scale, thusillustrates a representative relationship of the pole pairs to oneanother and to these fiexure strips. It will be apparent that theindicated magnetic select means, besides being convenient to implementand very clean in operation, long-lived, etc, is readily controlled. Forinstance, with inboard pole pairs 1-12 thus regularly disposed and souniformly arranged along the array of flexures, it is easy to arrangefor equal-strength selection/ release fields therealong. Moreover, sosizing and spacing these pole pieces and overlapping them with theirassociated flexures gives a highly efficient operation.

Another feature of the invention is the provision of two dummy coillessoutboard pole pairs, 27- /29-0 and 27-13/29-13 confronting no fiexures,as indicated. Those in the art will recognize that this helps greatly tonormalize the magnetic forces on the outboard fiexures (e.g., especially3-1 and 3-12) to be operated like the other fiexures. Provision of theoutboard stripper head units, sh1 and sh-13, also facilitates this.Where necessary, a pair of dummy outboard fiexures and associatedsolenoid units may also be added to optimize this effect, according tothe invention.

In summary, workers in the art will recognize the advantages in soactuating the interposers between off and on positions without the useof mechanical parts, but merely by the selective application of asolenoid current pulse. This eliminates the conventional and troublesomemechanical linkage used for this purpose, such as sliding interposerthrust means; restore cam means; associated alignment and guide meansfor the interposer and the linkage therefor, as well as synchronizationmeans to synchronize these mechanical parts with the punch bail; tosynchronize the restore cam with the interposer actuator, etc. It willbe appreciated that this eliminates many parts and a good deal ofexpense, both in fabrication and in adjustment needs. It also improvesreliability greatly, since these mechanical parts are fussy andtroublesome to make and to maintain, being prone to a good deal ofabrading Wear, for instance, being apt to drop out of synchronism, etc.It will also be appreciated that such selection means advantageouslycoact with the novel stripper arrangement whereby the stripper engagingmeans is hung centrally from the constantly reciprocating bail, leavinga good deal of room for access of the aforementioned magnetic selectionmeans. It will be appreciated that making the fiexures magnetic is asimple yet attractive way of making them responsive to such magneticselection means; especially when they are made part magnetic and partstructural.

I rzterposer Only one of the interposer assemblies IL will beparticularly described, it being understood that the companion assemblyIR is similarly constructed and arranged. Interposer assembly IL willfirst be generally described with respect to FIGURES l, 2 and 3, therebeing seen to comprise a thin, resilient, multifingered, interposerfiexure sheet 30 surrounded by a pair of spaced inner and outer guidesheets 5, 1, respectively. A spacer 13 separates outer sheet 1 fromflexure sheet 30. According to a feature of the invention sheets 1, 30,5 are clamped together and conjunctively flexed (deflected) inwardlyagainst stripper ST between a pair of inner and outer clamp bars 7, 15,respectively. Bar 15 is attached to bail H, as indicated moreparticularly in FIGURE 2. It will be generally understood thatinterposer sheet 30 comprises 12 interposer flexure fingers 3-1 through3-12 and is so disposed upon bail H that each of these fingers 3 may beengaged punchingly with an associated one of the punches (Pl through P12respectively) when carried by bail H into the downward punching phase ofthe punch cycle.

According to another feature, outer, nonpunching preform sheet 1 (sheet1' similar) comprises a flexible, nonmagnetizable metal sheet adapted tobe deflected by clamp bars in a prescribed manner so the free endthereof is engaged guidedly along one side of all the stripper heads shas indicated in FIGURES 1 and 2. It is found that the magnetic flux fromthe pairs of pole pieces 27/29 is able to pass relatively unaffectedthrough the cross-section of such a sheet to attract associated ones offingers 3 theretoward. Preform 1 thus serves as a guiding stop for theset of interposer flexures 3-1 through 31-12 which, in the nonpunching(OFF) positions thereof are held somewhat conformingly thereagainst andout of driving engagement with the associated (nonselected) punch whenbail H is depressed. Preform 1' is similarly related to associatedflex-ures 31 through 3'12. This conforming contact is indicated inFIGURE 5 for nonpunching flexure 3-1, the latter being pulled by thepermanent magnetic flux from associated poles 29-1/271 to curve againstpreform 1. Such conformed flexing of sheet 1 allows it to contact aflexure finger 3 very smoothly and evenly along its vertical lengthwithout distorting it, stressing it, shearing it, or vibrating it (nobounce). Sheet 1 thus acts as a stop-limiting member.

So forming the outer preform of a single integral sheet for guiding aset of interposer flexure fingers is obviously convenient. Moreover, thesolid sheet was found surprisingly effective in transmitting magneticflux from magnet assembly ML to the fingers, where it had been supposedpreviously that flux-notches in the sheet were required for this.Avoiding such notching of preform 1 obviously strengthens it, as well assimplifying its fabrication. However, one or several holes, such as hole1h in sheet 1 (FIGURE 3) may be provided to view the tips of adjacentinterposer fingers (e.-g. 3-1) for alignment thereof relative the topsof associated punches.

Similarly, inner punch preform 5 may be comprised of a flexible,nonmagnetizable metal sheet adapted to be deflected between clamps 7,against the side stripper ST with flexure sheet 30 bendingly engagedrelatively coplanar and conformingly thereagainst, thus establishing apre-flexed static condition thereof. Flexure fingers 3 are thusspring-biased to be urged into the ON position. The free end of preform5 may be slightly beveled for flatter, low pressure engagement againstthe stripper. Punch preform 5 is believed to function as a preformeddeflected beam curved to provide a prescribed stiffening reinforcementof associated interposer fingers 3, extending coextensive therewithalmost to their tip so as to prevent them from buckling when thrustagainst an associated punch. However, with sheet 5 so disposed justabove the tops of associated punches P1 through P12, it becomesnecessary to provide for clearing such punches when they are nonselectedsince sheet 5 is carried down therepast with bail H during punchingphase (FIG- URE 5). Thus, a set of 12 clearance cutouts C1 through C-12(FIGURE 3) are provided at this free end of sheet 5, each being disposedand dimensioned to clear an associated punch. Thus, cutouts C-l, etc.,are slightly wider than the enlarged punch heads PP and are cut deeplyenough to admit heads PP when bail H, with attached interposer assemblyIL, descends to its bottommost (Down) position. Punch phase (or Downposition) is indicated in FIGURE 5 where nonselected punch P-1 (headPP-l thereof) is indicated as having entered a corresponding cutout C-lin punch preform 5. Sheet 5 may thus be stamped out to include cutoutsC.

related to flexures 3'1 through 3'12.

Preferably, the flexure fiingers are arranged to be sufficiently wide tobridge associated ones of cutouts C (but little wider), beingdimensioned to overlap successive ones of the lands therebetween andthus be guided on both sides. Thus, the fingers will be somewhat widerthan associated punch beads which must fit within the cutouts.

Thus, according to a feature of the invention, a set of flexureinterposers associated with a row of punches, as well as the associatedinner and outer preforms therefor, are each formed from a singleflexible metal sheet, the sheets being mounted in common upon the punchbail and being clamped there to be preflexed in common (biased) incommon integral bending arrangement. The outer preforms (1, 1) may beformed to comprise a sheet about 3.125 by 2.359 inches with a thicknessof 18-20 mils found satisfactory for this embodiment. Both pairs ofpreforms (1, 1', 5, 5) are formed from a nonmagnetic material having ahigh degree of flatness (at least adjacent the interposer sheets 30,including fingers 3, 3' which are also very flat) being about twice thethickness of sheets 30, 30". For instance, a flatness in theneighborhood of 0.003 TIR has been found acceptable. It is preferred inthis embodiment to make inner preforms 5, 5' about 25 mils thick andouter preforms 1, 1 about 19 mils thick, Evidently, the preforms (1', 1,5', 5) must be somewhat thicker than the interposer sheets 30, 30 toexhibit somewhat more stiffness. Sheets 30, 30 will be magnetizable,light and highly resilient. For instance, it may preferably be about 10mils thick, with spacers 15, 15 about the same. Sheets 30, 30' maycomprise 10-10 cold-rolled steel or blue spring (1095) high-carbonsteel, or other hard nonmagnetic steel and will also includeferromagnetic material, inserted therein or clad thereon, as indicatedbelow.

Workers in the art will appreciate many advantages from mounting theinterposer assemblies IR, IL on the bail H. One such advantage is thatthe stripper ST may project from bail H to guide interposer elements,yet with no rubbing between these members at any time. Moreover, thestripper heads sh and the surface of the stripper body may also act toposition the preform guides.

Flexure characteristics FIGURES 2 and 5 will be seen to supplement FIG-URES 1 through 3, showing a section through both interposer assembliesIR, IL in illustrative operating relation with associated portions ofstripper ST and respective punches. It will be assumed in FIGURE 2 thatthe entire assembly is in Bail-up phase where the punches and flexureinterposer fingers are all disengaged. Thus, those punches that punchedin the preceding cycle will be understood as having just been returnedto Up position by the stripper. The punches are all understood as beingretained Up, offset above stripper heads sh a prescribed clearance(e.g., about 4 mils) by the retainer means (e.g. springs sp) asaforesaid. The punches thus present their top surfaces aligned along aprescribed Up-plane RR (FIGURE 2) by stop means SX (above). Plane R-R isarranged to be spaced below the engaging tips of the interposer flexures3, 3' a prescribed amount (gap d here about 10 mils). With thisarrangement, there will be no appreciable impact between an interposerflexure and the associated punch head when the two are engaged sinceengagement will occur very close to the top of the bail stroke whererelative velocity (along V axis) is close to zero. Thus, a gentle,smooth engagement of interposer with punch is achieved, something verydesirable in the art. For illustration purposes, it will also beunderstood that, in FIG- URE 5, one of the interposer flexures (3-1), isnonselected, i.e. has been pulled out of punch position and into nopunch position (from ON to OFF position, as indicated by the arrow)where it may clear (not engage) associated punch P1 when thebail/stripper mount supporting it is so depressed in this punch phase.On the other hand, fleXure 31 is seen selected, i.e., allowed to snap toON position by select-current fields and is thrusting punch P'l. Asaforesaid, punches P, P are indicated as having separately formed headsPT of a high durability, nonmagnetic material welded thereon.

According to the invention, a modification of the interposer flexurestructure may be effected whereby flexures 3, 3 are fabricated in acompound structure having a tough, durable, resilient structural portionI-A (e.g. of a hard spring steel) and a high mu, ferromagnetic (e.g.soft iron) portion I-B, bonded intimately to portion IA. For instance,it has been found that cold-rolling such a sheet of soft iron onto asheet of (high carbon) blue spring steel under high pressure canmolecularly bond the two together into a satisfactory compoundinterposer fiexure. These layers must be very intimately bonded so that,when flexed, they deflect as a substantially integralbeam element,without experiencing any appreciable internal stresses, such asdifferent shear stresses which might tend to part the layers, especiallyat the clamping point. In an alternate form, the fiexures may comprise athree-part sandwich having a pair of outer spring steel sheavesmolecularlybonded to an intermediate ferromagnetic iron layer. It hasbeen found that the mechanical strength and durability of compoundflexures so fabricated is improved without sacrificing any neededmagnetic-attraction characteristics. Workers in the art will visualizeother equivalent ways of providing these two different materials in sucha composite interposer flexure.

According to another feature which may be used either instead of, ortogether with, the aforementioned multilayer construction of flexures 3,3' is the provision of a wear tip IT on the free end of the fiexurefingers to be engaged with the top of a respective punch. Moreparticularly, it has been found that welding a relatively thin layer ofwear material, such as Stellite, onto the tips of interposers 3, 3 andthereafter machining, or otherwise forming, these tips to conform to thedesired precise dimensions, squareness, etc., reduces the likelihood ofabrading wear thereof by the punch. Such wear is especially troublesomein tending to make the tips nonsquare so that they engage the top of arespective punch unevenly. Such oblique engagement can quickly lead tomisaligned punching actuation and also accelerate the further wear ofthe two parts, e.g., by gouging out of the top of the punch because ofthe reduced en- Y gaging area, etc.

Interposer operation FIGURE 5 is somewhat similar to FIGURE 2 showingroughly the same cross-sectional area, but at a different phase in thepunch cycle, that is, at the punching (or Baildown) phase of the cycle,where FIGURE 2 illustrates res phase (Bail-up). FIGURE 5 illustratesselected and non-selected interposers and punches. Thus, interposer 31is seen in the selected (interposed, punch-thrusting) condition, as isassociated punch P1. Conversely, companion interposer 31 is seen in thenon-selected (noninterposed) condition, and associated punch P-l isnon-selected and non-punching.

The interposer assemblies are seen here arranged symmetrically aboutcentral bail H and stripper frame ST projecting therefrom, as in FIGURES1-3 above. Initial stripper head sit-1 is shown engaged with outerpreforms 1, 1 to space and flex them properly. Inner preform 5 is seenas guiding interposer 3'1 to thrust associated punch P'-1 downwardsufiicient to effect punching, bail H and stripper ST having bottomed atthe punching phase in this driving cycle. Selected" flexure interposer3'1 is thus understood to be in conformed, guiding, stiffeningengagement against preform 5. The magnetic interposer-select means isfragmentarily indicated by lower pole pieces 29, 29 and their associatedsolenoids 29-31, 2931 respectively. It will be understood that selectionof flexure 3'1 was effected by effectively nullifying the pull of thepermanent magnet flux from associated pole pieces 271, 291, thuspreventing these from pulling flexure 3'1 into nonselected (OFF)position against outer preform 1'. As aforesaid, this is done byapplying a select current pulse through coils 2'31, 27'31. The resultantbucking (select) field thus releases flexure 31 to return itself intoengagement against inner preform 5'. The preflexing of the interposerflexures assures this self-return action. On the other hand, companionflexure 3-1 will be seen as pulled outwardly against associated outerpreform 1 by the permanent mag net flux from associated pole pieces 271,291, there evidently being no bucking (select) field from associatedsolenoids 29-31, 27-31. Thus, flexure 3-1 is kept clear of punch headPP-l of associated punch P-l when it is depressed with the bailassembly, as shown in this punching phase. Head PP-l avoids contact withinner preform 5 by riding up into the associated slot C-l thereinprovided for this, as indicated. It will further be appreciated thatnon-selected punch P-1 will be maintained in this UP condition (byretainer spring sp), being ready, when the bail assembly has returnedupwardly, to begin the next punching cycle. However, selected punch P'1will be therewhile engaged in stripper grooves pg, by associatedsurrounding stripper heads sh-I, sIz-Z (sliding along these grooves) andwill be returned to the UP position for beginning the next cycle. Itwill be recognized that it is thus a feature of the invention that themagnetic interposer selecting means are relatively fail-safe, in that,being held normallyoff, they are less likely to produce erroneouspunching, e.g., as might occur if no punch pulses were required to clearthe interposers and failed to occur.

The features of the above-described improved interposer arrangements maybe summarized as follows, with particular reference to FIGURES 2 and 5.As aforesaid, a feature of the invention is that the interposer flexuresdo double duty, serving both as the armature of the selecting solenoidmeans and as the mechanical interposer linkage. Furthermore, thislinkage function is provided without any abradng parts and with a small,compact, lowmass unit. Each row of interposers may be considered asbeing clamped between a pair of relatively stiff (preform) guide means,the overall assembly being mounted on the stripper-bail frame so thatthese guide means are preformed into a prescribed flexed curvature andcarry the interposer flexure with them to be similarly pre-flexed. Thus,in the nonpunching position an interposer will be held aganst the outerpreform so that it cannot engage the top of the associated punch. Whenbail-stripper ST is in UP phase, starting a punch driving cycle,selected interposer flexures are released to snap into engagement withthe inner preform where as the downstroke of the bail begins, they mayengage the top of the associated punch as to thrust them punchingly. Asthe punching load is applied and stripper ST thrusts downwardly, towardthe die D and the perforable record therebeneath, the thin selectedinterposers transmit this thrust to respective punches smoothly andfirmly, being reinforced and stiffened by the inner preform. Thedeflected, guided flexu-res thus react like a rigid column to transmitthe required punching force without buckling. Since both the preformsand the flexures have a common point of attachment (to bail H) there canbe no relative sliding motion or resultant abrasion, etc. between themand therefore no relative wear. 1

The deflected beam preforms 1, 5 are a feature of the invention thatprovides convenience as Well as efliciency since they avoid the fussymanufacturing problems that would be inherent in providing the bailframe with contoured guide surfaces. That is by deflecting preforms 1,

13 in common with their associated intermediate flexure interposer, apair of guiding, conformingly contoured surfaces is automaticallyprovided.

Since the interposer assemblies IL, IR are carried by reciprocating bailassembly and since selection is performed magnetically, the relativemotion and abrasion which normally exists in prior art machines betweenthe reciprocating and fixed members is eliminated, as is any resultantwear. The interposers, being held in a normally non-punching position bya permanent magnet field, move to punch position in a snap-flexingaction because of their inital flexing preload, doing so, of course,when the (bucking) releasing field is applied from associated solenoidcoils. Translation of the interposer from non-punching to punchingposition will be understood to occur at the top of the up-down stroke ofthe bail when a clearance is established between the punch and theinterposer, for instance, when the punches are in the condition shown inFIGURES 2 and 7. Thus, the punch selecting interposer system of theinvention has only one moving part, and that part a simple flexure meanswhich has no sliding, abrasive pivoting or impacting motions. No priorart interposer system is known which can claim these highly desirablecharacteristics.

Equivalent magnetic interposer translating arrange ments may be providedaccording to the invention for other actuator arrangements where theselectable actuation of driven members is accomplished by selectablecoupling thereof with a driving flexure member. Such systems may beprovided for the actuation of print hammers in a high speed computerprinter apparatus, other record marking appartus, or the like.Equivalent interposer means and selection means will occur to thoseskilled in the art.

While in accordance with the provisions of the patent laws, the abovehas illustrated and described preferred forms of the invention and theirmodes of operation, it will be apparent to those skilled in the art thatchanges may be made in the apparatus described without depart ing fromthe spirit and scope of the invention as set forth in the appendedclaims, and that, in some cases, certain features of the invention maybe used to advantage without a corresponding use of other features andcertain features may be changed or substituted for, equivalently, asappreciated by those skilled in the art.

Having now described the invention what is claimed as new and desired tobe secured by Letters Patent is:

1. Apparatus for selectively actuating driven means comprising bendingguide means; elongate flexible interposer means disposed in flexedengagement with said guide means, said guide means being adapted to soengage said interposer means as to bias it flexingly into a prescribeddriving condition along a prescribed driving path along which saidinterposer means may drivingly actuate said driven means; drive meansarranged to periodically thrust said interposer and guide means togetheralong said path; and coupling control means for selectively displacingsaid interposer into and out of said path, and thus out of said drivingrelation with said driven means; continuous nonmagnetic limit meansinterposed between said interposer means and said control means so as tointercept the working flux gap and being adapted for limiting the saiddisplacement of said interposer means out of said path; said interposermeans comprising a ferromagnetic strip; each said control meanscomprising an opposed first and second flux-generating means adapted anddisposed to urge said associated ferromagnetic strip into and out ofsaid driving condition.

2. The combination as recited in claim 1 wherein said driven meanscomprise at least one set of aligned reciprocable marking elements;wherein said interposer means comprises a set of ferromagnetic preflexedflexure strips aligned with each said set of elements, each strip beingdisposed to engage a respective one of said marking ele- 'ments whenassuming said driving condition, said first magnetic flux generatingmeans including a plurality of magnetic pole means, one thereof beingdisposed in fluxcoupled relation with each of said strips forselectively controlling said urging relative said driving condition.

3. The combination as recited in claim 2 wherein said control meanscomprises one set of aligned pairs of pole pieces for each set ofinterposer strips, each pair of pole pieces being operatively disposedadjacent the nondriving position of a deflectible portion of arespective strip and including solenoid energizing means for selectivelyenabling the deflection of said associated strip portion into saiddriving condition; said set of pole piece pairs being operativelyassociated with a common permanent magnet means for energization thereofto normally urge said associated strip portions into said non-drivingposition except when opposed by said associated solenoid energizingmeans.

4. The combination as recited in claim 3 wherein adjustable flux-shuntmeans is provided coupling each said set of pole pairs with saidassociated magnet means, being disposed in adjustable flux-shuntingrelation across the poles thereof.

5. The combination as recited in claim 4 wherein each said solenoidmeans includes a solenoid winding about each pole piece in saidrespective pair and is adapted to be selectively energized for providingsolenoid flux arranged to cancel the permanent magnet fluxemanating fromsa d respective pole pieces to thereby release said associated prebiasedstrip to flex itself returningly to said driving condition.

6. The combination as recited in claim 5 wherein is also provided twopairs of outboard pole pieces each being arranged to normalize themagnetic effects upon a respective adjacent outboard strip and thusassure uniform magnetic flux distribution across said set of stripswithout edge effects.

7. The combination as recited in claim 6 wherein is also provided foreach said set of strips an integral, relatively continuous nonmagneticouter guide sheet disposed adjacent and between said associated polepieces and said strips as disposed in said nondriving position forconformed stop-limiting engagement with said strips there, being mountedto be reciprocated in common therewith.

8. The combination as recited in claim 7 wherein said driving meanscomprises a constantly oscillating punch bail; wherein said markingelements each comprise a punch, each of said punches being provided witha nonmagnetic wear tip adapted to prevent the magnetically inducedtranslation thereof.

9. The combination as recited in claim 8 wherein said apparatuscomprises a high-speed punch assembly for selectively and encodinglyperforating data processing records in response to prescribedcharacter-encoded punch signals, said punch assembly comprising aperiodically reciprocating bail member; at least one array of alignedpunches, each being arranged to be selectively displaced along anassociated punch path in response to occurrence of associated ones ofsaid character signals; said bail member also including stripper meansprojecting therefrom to be periodically reciprocated in synchronismtherewith, said stripper means comprising a plurality of punchretractorheads disposed in alignment to be in retracting engagement withassociated ones of associated punches; an array of flexure meansoperatively associated with each said punch array and mounted on saidbail member to be reciprocated therewith, said array comprising aplurality of aligned flexures each being associated couplingly with arespective one of said punches and comprising an elongate planar springmember predeflected to normally assume a first condition adapted forcoupling engagement with said associated one of said punches also beingadapted to be selectively flexed and translated out of said firstcondition into a second noncoupling condition; each said flexure arrayalso including a guiding sheet member associated deflectingly with saidflexures, being clamped in common therewith against said bail member todeflect them together, conformingly and stilfeningly; and interposertranslate means comprising said set of pole piece pairs associated witheach said array of flexure means, each pole pair thereof being disposedin operative relation with one of said flexures for selectivetranslation thereof into said first condition responsive to occurrenceof a prescribed one of said punch signals.

10. The combination as recited in claim 2 wherein each said plurality ofpole means is operatively associated with a respective said set ofstrips and also includes permanent magnet flux-generating means coupledin common therewith.

11. A marking arrangement for marking data processing recordscomprising:

record marking means selectably movable along a prescribed marking pathbetween a marking and a nonmarking position; driving means continuallyoscillating along a prescribed drive path spaced from said marking path;interposer means disposed between said driving means and said markingmeans for selective coupling thereof, said interposer means comprisingat least one elongate flexible cantilevered ferromagnetic strip and aguide means engaged with each said interposing strip for flexing thereofso that the free tip is normally disposed in a driving condition along acoupling path between said drive and marking paths for drivingengagement with said driven marking means; and bidirectional magneticcontrol means disposed in flux-coupling relation adjacent saidinterposer strip and adapted to selectively actuate said tip thereofinto said driving condition and out of said driving condition to anondriving condition, to thus control actuation of said marking meansfrom said nonmarking to said marking position; continuous limit meansdisposed in working-gap flux-intersecting relation between each saidstrip and said associated control means for defining said nondrivingcondition, said control means including first magnetic means for urgingsaid tip in one of said conditions and second, selectible magnetic meansfor urging said tip oppositely into the other of said conditions.

12. The combination as recited in claim 11 wherein said marking meanscomprises at least one set of individually, selectably actuable markingelements reciprocable between respective marking and nonrnarkingpositions; wherein said interposer means comprises a set of prefiexedmagnetic spring members for each said set of marking elements, saidmembers being deflectable in substantially one resilient axis only, onesaid spring memher being arranged for engagement with each one of saidmarking elements; and wherein said magnetic control means comprises aset of pairs of magnet pole pieces for each said spring member set, onepair of pole pieces being disposed operatively adjacent each of saidspring members along said resilient axis for selective translationthereof into said conditions to thus control said selective marking.

13. The combination as recited in claim 12 wherein each said set of polepiece pairs is operatively disposed with a common permanent magnet toprovide said first magnetic means; wherein each said pair of pole piecesis provided with selectively energizable solenoid means to provide saidsecond magnetic means.

14. The combination as recited in claim 13 wherein adjustable flux shuntmeans is provided intermediate each said permanent magnet and associatedones of said pole piece pairs for controlling said urging thereof.

15. Apparatus for selectively actuating driven means comprising bendingguide means; elongate flexible interposer means disposed in flexedengagement with said guide means, said guide means being adapted to soengage said interposer means as to bias it flexingly into a prescribeddrivingcondition along a prescribed driving path along which saidinterposer means may drivingly actuate said driven means; drive meansarranged to periodically thrust said interposer and guide means togetheralong said path; and coupling control means for selectively displacingsaid interposer into and out of said path, and thus, selectively, out ofsaid driving relation with said driven means; said interposer meanscomprising a ferromagnetic strip; each said control means comprising apair of solenoid pole pieces arranged to project from a prescribed baseplane into operative adjacency with a respective interposer strip so asto be capable of electromagnetically translating the strip, these piecesbeing separated along this plane by a prescribed base-gap; permanentmagnet means adapted to be coupled to both said pole pieces across saidbase-gap so as to project a prescribed permanent-magnet fluxtherethrough for operate coaction with said respective strip; andshunt-return means arranged between said magnet means and said polepieces so as to bridge at least a portion of said base-gap relativelyalong said plane and to thereby provide a shunt for returning aprescribed portion of said permanent magnet flux to said magnet means aswell as also providing a prescribed low-reluctance return path betweensaid pole pieces along said base plane and thereby eliminatingcross-talk leakage to adjacent control means; said shunt-return meanscomprising material of prescribed reluctance extending across at least aportion of said base-gap.

16. The combination as recited in claim 15 wherein said shunt returnmeans material extends completely across said base-gap.

17. The combination as recited in claim 16 wherein said solenoid polepieces are adapted to selectively pull said strip out of said drivingcondition and wherein said permanent magnet flux is adapted to hold thestrip so pulled.

18. The combination as recited in claim 17 wherein there is alsoprovided a continuous non-magnetic limit means interposed between saidinterposer means and said control means for limiting the saiddisplacement of said interposer means out of said driving path.

References Cited UNITED STATES PATENTS 3,104,053 9/1963 Rabinow 234119 X3,232,525 2/1966 MacNeill et a1 234-33 3,279,690 10/ 1966 Masterson234--115 3,307,781 3/1967 Jones 234- X WILLIAM S. LAWSON, PrimaryExaminer.

